Advantages

With late binding of the User Interface/Presentation, you can achieve:

Single authoring

Device independence

Accessibility out of the box

Backplane Implementation

The XG worked on XForms, XHTML, SMIL, RDFa, SVG, ODF (E.g. spreadsheets with
live graphics)

Conclusion

In the light of the emerging trend to implement XML vocabularies in
Unobtrusive Javascript libraries, we recommend work on standardising the
interface between the libraries, so that vocabularies can work together
seamlessly, and without prior negotiation.